Thin mediums of material such as paper, film and fabric have many useful applications. Often images and information are recorded on such mediums. Where information regarding characteristics of the medium is known in advance of the recording process, the recording process can be adjusted to improve the quality of the recording. Once a recording has been made on a medium it can be useful to associate electronic information in a memory that is associated with the medium. Such electronic information can include information that describes the chain of custody of the medium, the use of the medium, and who has accessed the medium. Radio Frequency Identification (RFID) tags typically comprise three principal elements, an antenna and transponder that cooperate to send and receive electromagnetic fields containing information and a memory that stores information. Other useful information can also be associated with the medium such as electronic information that depicts information recorded on the medium. See for example, commonly assigned U.S. patent application Ser. No. 10/161,514, entitled Virtual Annotation of a Recording on an Archival Media, filed by Kerr et al. on Jun. 3, 2002.
It is known to use Radio Frequency Identification (RFID) tags to provide the electronic memory and communication capabilities that allow electronic information to be associated with a medium.
The RFID tag is adapted to exchange information with a co-designed reading/writing device. Information that is stored in an RFID tag that is joined to an item can later be used to track, identify and process the item. The RFID tag can also store other information that is to be associated with the item. A commercially available “TAG-IT INLAY”™ RFID tag available from Texas Instruments, Incorporated, Dallas, Tex., U.S.A., can be used to provide identifying information about an item to which it is attached. This relatively thin, flexible type of RFID tag can be used in applications that previously required a label or bar code. The RFID tags of the prior art are typically used for identification purposes, such as for employee badges, inventory control, and credit card account identification. The advantage of such RFID tags is that they are small in size, easy to communicate with and unlike a bar coded item, do not require the item to be aligned to the reader or scanner.
RFID tags have been proposed for use in applications with passports and credit cards, such as is disclosed in U.S. Pat. No. 5,528,222 filed by Moskowitz et al. These devices are useful for tracking the location, characteristics and usage of documents, books and packages. For example, such tags can be used to track the location of documents and track the chain of custody of such documents within a document management system.
RFID tags are typically formed into a package such as an inlay, a plastic glass or ceramic housing. The RFID package is then joined to an item such as a document or book after the item has been fully assembled. Typically the RFID tag has an adhesive surface that is used to form a bond between the RFID tag and the item to which it is being joined. It is also known to use other ways of mechanically joining an RFID tag to an item. For example, an RFID tag can be joined to an item using a staple or other mechanical fastener.
There is room for improvement in this arrangement. For example, a poor bond or poor mechanical joint between the RFID tag and the item can result in separation of the RFID tag from the item. This can defeat the purpose of joining the RFID tag to the item. Further, joining an RFID tag to an item increases the cost of the combined RFID tag and item because the RFID tag must include the cost of both the base and the fastener and the cost of labor associated with joining the RFID tag to the item. These costs can become significant where RFID tags are to be joined to a multiplicity of individual items, for example, individual sheets of medium such as film or paper.
Additionally, such RFID tags typically take the form of a patterned antenna located on a base having a transponder unit applied to the top of the antenna. Accordingly, such RFID tags have a non-uniform cross-sectional area. The non-uniform cross-section of the tag can make the tag vulnerable to incidental damage to contact during manufacturing, printing, use, storage and distribution. Further, such RFID tags can interfere with the appearance and the use of the item.
One approach for solving these problems is to incorporate RFID tags inside an item such as an identification badge. In one example, this is done by providing a clam shell type outer casing into which the RFID and antenna electronics are deposited. An example of such an identification badge is the ProxCard II proximity access card sold by HID Corporation, Irvine, Calif., U.S.A. Thinner cards are made by sandwiching the RFID and antenna electronics between sheets of laminate material. An example of such a badge is the ISO ThinCard sold by HID Corporation, Irvine, Calif., U.S.A. While this method of forming a card produces a card that is thinner than the clam shell type card, the card has an uneven cross-section with increased thickness in the area of the RFID electronics.
These techniques, however, are not feasibly applied to the task of forming a thin medium such as paper, film and fabric. Such thin mediums are typically fabricated in high volumes using coating, extrusion and rolling techniques to convert pulp, gelatin or other material into thin sheets of material that are then processed into useful forms. The addition of clam shell type structures known in the art is not practically or economically feasible in this type of production. The alternative lamination approach of the prior art is also not preferred because the increased thickness and uneven cross section caused by the presence of RFID electronics and antenna sandwiched between laminations, can interfere with subsequent fabrication processes causing damage to fabrication equipment and the RFID electronics and or to the medium itself. Further this uneven cross section can interfere with imaging equipment and medium when the laminated medium having an RFID unit is passed through equipment such as a printer that uses a medium after formation. This interference can damage the RFID tag, the medium and the equipment that uses the medium. The uneven cross section also creates a less than desirable appearance for the medium and images that are subsequently recorded thereon.
Thus a need exists for a medium that has the ability to store and electronically exchange data with the medium being compatible with conventional web fabrication processes and post fabrication uses of the medium.